Jason Collins became the first active player in America's four major professional team sports to come out as gay. Given sports' elevated place in society, Collins might have just made a significant step for gay rights.

Washington — National Basketball Association center Jason Collins on Monday became the first male professional athlete in a major US team sport to reveal that he is gay.

In a lengthy post co-written with Sports Illustrated reporter Frank Lidz, Mr. Collins writes that after years of hiding his sexuality, March’s Supreme Court oral hearings pushed him to come out of the closet.

“Less than three miles from my apartment, nine jurists argued about my happiness and my future. Here was my chance to be heard, and I couldn’t say a thing,” Collins wrote.

Collins, who played for the Washington Wizards this year, waited until the season was over so as to not be a distraction to the team. Then he contacted Sports Illustrated through his agents to make the disclosure, according to an accompanying article.

“I’m glad I’m coming out in 2013 rather than 2003. The climate has shifted; public opinion as shifted. And yet we still have so much farther to go,” Collins concluded.

He is now a free agent but has said he wants to keep playing.

Will Collins’s move affect US public policy? To a certain extent, he is taking advantage of an existing trend toward more tolerance of gay rights in US public opinion. Earlier this month, an NBC/Wall Street Journal survey found 53 percent of respondents approving of gay marriage, up two percentage points from December.

The more personal gay rights appear to Americans, the more support for it seems to grow. That’s what happened with Sen. Rob Portman (R) of Ohio, who announced in March that he has switched his stance and now supports gay marriage, in part because his son is gay.

Collins’s disclosure is likely to put wind in the sails of this trend, given the coverage it is likely to receive and the interest major league team sports generate in the United States, indeed the world. He is a tough, veteran center who was an all-American at Stanford University and a first-round draft pick of the Houston Rockets. He’s spent significant time playing for the New Jersey Nets and the Atlanta Hawks, with stops in Memphis, Minnesota, Boston, and now Washington along the way.

Of course, this trend is still partisan, and the Collins story may not change that. In the NBC poll, 73 percent of Democrats and 54 percent of independents approved of gay marriage, while 66 percent of Republicans opposed it.

Collins was a roommate of Rep. Joe Kennedy III (D) of Massachusetts in college. Kennedy has already issued a statement of support for Collins and invited him to march in the 2013 Gay Pride parade in Boston.

Ex-President Bill Clinton was also quick to weigh in, as Collins was also a classmate and friend of his daughter, Chelsea, at Stanford.

“Jason’s announcement today is an important moment for professional sports and in the history of the LGBT [lesbian, gay, bisexual, transgender] community,” said Mr. Clinton’s statement in part.

Clinton also said he hoped that the larger NBA community would accept Collins for who he is. Notably, Los Angeles Lakers star Kobe Bryant tweeted on Monday that he was “proud” of Collins.

“Don’t suffocate who u r because of the ignorance of others,” Mr. Bryant tweeted.

The effect of the Collins announcement would be more pronounced if other male pro athletes follow his example. Former Baltimore Ravenslinebacker Brendon Ayanbadejo, who is straight but has expressed support for gay rights, has said that there are as many as four National Football League players whom he knows to be gay, and that they have been discussing coming out as a group.